PREOPERATIVE EVALUATION OF INTERRADICULAR SPACES AND CORTICAL BONE THICKNESS FOR PLACEMENT OF MINI-IMPLANTS BY CONE BEAM COMPUTED TOMOGRAPHY

Objectives. This study was performed to measure the available mesiodistal interradicular distance. cortical bone thickness and alveolar bone width between second premolar and first molar as the suggested site for mini-implant placement by using cone beam computed tomography (CBCT). Study design. Three dimensional CBCT images of twenty two patients (10 males. 12 females; age range. 18-37 years; average age, 22 years) were examined. Maxillary and mandibular interradicular distances, cortical bone thickness and alveolar bone width between second premolar and first molar were measured at 4 vertical levels from the cementoenamel junction (CEJ). Results. Maxillary interradicular distances ranged from 2.93 to 3.33 mm and tended to increase from the eEl to the apex. Mandibular interradicular distances ranged from 2.93 to 3.42mm and tended to be greater than maxillary interradicular spaces. Maxillary buccal cortical bone thickness was 0.8 to 1.32 rnm and mandibular buccal cortical bone thicknesses was 1.2 to 1.86 mrn. In both jaws. buccal cortical bone thickness tended to increase from the Cf.J to the apex. Alveolar process width of the maxilla and mandible were 10.16 to 11.94 mm and 8.88 to 10.92 respectively. Conclusion: Evaluation of cortical bone thickness is Important because it is the major determinant of initial stability of a rnicroimplant. According to our results we expect 1.2 mm or more of cortical bone thickness between the second premolar and first molar at 4, 6 and 8 mm from the Cfil. Iuterradicular space availability is related to safety of mini-implant insertion. The recommended safe locations for mini-implant placement are at 6 or 8 rnrn apical to eEl between the second premolar and the first molar in the maxilla or the mandible.